\subsubsection{Centre of Mass to Centre of Contact Points}
The Centre of Mass to Centre of Contact Points (CMCCP), is a simple quality measure based on the positioning of the contact points on a given object. The hypothesis is that a good grasp is one where the average contact point is close to the object centre of mass.

\noindent The basic principle of the CMCCP quality measure is shown in figure \ref{fig:cmccp}. The 2D case is shown for convenience. Given an object with a centre of mass ($COM$) and two contact points respectively $CP_1$ and $CP_2$ the measure is based on the distance from the average position of the contact points to the object centre of mass. The distance is then normalized in between 0 and 1 with the maximum distance from the object centre of mass to the object edge. This results in a measure between 0 and 1 where 0 is a bad grasp and 1 is a good grasp. In equation \ref{eq:cmccp} a formal description of the quality measure is shown.
\begin{equation}
Q_{CMCCP} = 1-\frac{|| COM - \displaystyle\sum\limits_{i=1}^n \frac{CP_i}{n}||}{\mbox{MaxDistance}}
\label{eq:cmccp}
\end{equation}
\begin{figure}[H]
\centering
\includegraphics[width = 0.3\textwidth]{figures/cmccp.pdf}
\caption{Illustration of the basic principle of the CMCCP quality measure, shown in 2D. $CP_1$ and $CP_2$ being the contact points and d being the distance from the average contactpoint $CP_{avg}$ to the objects centre of mass, $COM$.}
\label{fig:cmccp}
\end{figure}


